In Situ Infrared Ellipsometric Study of Stimuli-Responsive Mixed Polyelectrolyte Brushes
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- 作者：Yulia Mikhaylova ; Leonid Ionov ; Jö ; rg Rappich ; Michael Gensch ; Norbert Esser ; Sergiy Minko ; Klaus-Jochen Eichhorn ; Manfred Stamm ; Karsten Hinrichs
- 刊名：Analytical Chemistry
- 出版年：2007
- 出版时间：October 15, 2007
- 年：2007
- 卷：79
- 期：20
- 页码：7676 - 7682
- 全文大小：471K
- 年卷期：v.79,no.20(October 15, 2007)
- ISSN：1520-6882
文摘
The switching behavior of stimuli-responsive mixed polymer brushes (d = 11 nm) was monitored for the first timein liquid phase in situ by infrared spectroscopic ellipsometry (IRSE). IRSE is presented as a new, sensitive in situtool for online analysis of chemical changes in a thincomplex film at the solid/liquid interface. Responsivebehavior (protonation and deprotonation reaction) of thepoly(acrylic acid)/poly(2-vinylpyridine) (PAA-mix-P2VP)brush was probed in aqueous solutions with pH rangingfrom pH 2 to pH 10. Structural and chemical changes ina thin polymer brush layer were identified from theanalysis of infrared ellipsometric tan spectra during thevariation of pH. Systematic change in pH confirmed thereversible switching behavior of the PAA-mix-P2VP brushbetween three different states: swollen P2VP and compact PAA chains at pH 2, a compact "P2VP...PAA"complex at pH 6.5, and swollen PAA and compact P2VPchains at pH 10.